In cholestasis syndrome, the change of bile acids, salts, endotoxins and opioidsis is accompanied with hepaticencephalopathy and brain trauma; therefore, in this study, the histopathological changes of hippocampus after bile duct ligation were investigated. This study was performed on male Wistar rats. The rats were divided into three groups, namely the control, sham and cholestatic groups. After two weeks, the rats were killed under anesth-esia and their brains were dissected with no delay. The specimens were processed routinely and were sectioned into slices of 6-micron thickness. The sections were stained by Hematoxiline-Eosin (H&E) method. Subsequently, they were studied using optical microscope. Necrotic cells, the diminution of cell density and wrinkled chromatic nuclei were observed in hippocampus section. In addition, the thickness of hippocampus was mostly decreased. However, in the sham and control groups no changes were observed. Since endotoxin causes tissue trauma, the increase of en-dotoxin may result in tissue changes in the brain.